Polycarbonate resins are well-known thermoplastic resins which have long been used in a variety of applications requiring resistance to impact. At low temperatures, generally lower than 20° C., polycarbonate becomes brittle and its utility is thus limited by this shortcoming. It is known that the low temperature impact strength of polycarbonate may be improved upon by the introduction of silicone blocks into the polycarbonate structure, as disclosed in U.S. Pat. Nos. 3,189,662; 3,419,634; 4,123,588; 4,569,970; 4,920,183 and 5,068,302.
The previous attempts to address low temperature impact strength, using additives, blends, and copolymer techniques, however, have not been successful in achieving low temperature impact strength while maintaining optical clarity.
Consequently, there is a need for new, cost effective materials that can provide improvements in low temperature impact strength while maintaining high optical clarity and that can therefore overcome the deficiencies of the conventional blends, additives, and copolymers.